Stuck Mash Again!

I've brewed all grain for almost a year now and have been using the 5gal cooler mash tun with stainless braid with no issues. Two brews ago I decided I wanted to squeeze a few more efficiency points out so I switched to the cooler false bottom from morebeer.com I also decided to rig up a gravity system so I could try fly sparging. My first brew ingredients:

7.5 lbs of 2 row
1lb carafoam
1lb crystal 15

I added 12 quarts of water to make a mash temp of 152.

Everything was going fine until I go to vorlauf when I cracked the valve and a little comes out then it stops completely. Not even a drip comes out. I tried everything: mash out, blowing in the tube, stirring, blowing water into the tube nothing would un-stuck the mash. I ended up having to transfer the mash into another cooler then clean the false bottom and it worked the second time.

My second brew was very similar ingedients and the same exact problem. Couldn't unstuck the mash had to transfer into another cooler but even then it didnt un stuck the mash so I pulled out my old stainless braid and that did the trick.

I'm frustrated and put off that spending the extra money to improve my system has led to disaster. Any advice?

The false bottom is connected to the valve with some 3/8" silicone tubing. After the valve I have 3ft of 3/8" tubing into my boil kettle.

Thanks for any advice! Love the forums!

Use rice hulls and/or if you are milling your grain, loosen the gap a bit. You may also need to try to raise the temp to 165 for mash out. I never do this but I hear that works good. I would try a pound of rice hulls next brew.

I agree with the rice hulls, but I think 1 pound is too much. I usually just throw in a double handful, works for me.

I did try probably a quarter pound of rice hulls in my second batch. I also tried not stirring the mash because I was afraid that the first time I may have got some grains under the false bottom and somehow clogged it, I don't it was a guess. I use the mill at the homebrew supply store to mill all the grains so I have trouble thinking that the crush size is the problem.

Maybe next time I try adding a bunch more rice hulls and see if that helps.

Yeah the rice hulls help a lot. And. Stir that mash, draw off into a cup slowly and pour back on top of the mash for a while. I have also found if my mash thickness is too thin I have too compact a grain bed by the time i start sparging. That's just me others will disagree.

Hate to say it man, but go back to the braid! If it ain't broke don't fix it! But I do understand though, I've certainly lusted after brewery upgrades and been less than impressed. I'm a proud SS braid batch sparger, and I regularly get 90+% efficiency with a tight crush and some rice hulls, and IMHO it's way easier to add a $1 pound of malt to your brew to make up for efficiency than to spend all that time fly sparging and spending good cash on a false bottom. Contact morebeer and tell them their false bottom sucks and you want your money back, and go back to the braid

Noting the Obvious aside from rice hulls..
Is the fit for everything correct? Double check its assembled tightly? I know that the spigot for my mash tun likes to wander a little bit if I assemble hoses to it from time to time.

Also as mentioned draw off very slowly and recycle your initial couple of quarts of wort. When I do my initial draw I'm very cautious and let it trickle in for a moment or two before opening it up very gradually to give things a chance to settle properly.

Also what are you mashing? Rye, Flaked anything in large amounts will create messes.

Also from my experience by not having not done so.. I mix up all the crushed grains as evenly as I can in the bucket before I pour them in to my mash tun. I do use rye and flaked grains a lot and I suspect that evenly distributing these items helps with extraction and uniform settling.

Just some thoughts to further muddy the water.

I don't use many flaked grains or rye, actually I think I've only used oats in one brew ever. It's a problem in almost any hobby, you buy upgraded equipment to solve a problem and it opens up twice as many more complicated problems!

For my next brew this is what I'll try: 0.5-1lb of rice hulls, no adjuncts, stir well during mash, crack valve very very slowly, add more strike water than normal (maybe 1.5 quarts per lb of grain?)

As for fitment, everything seems snug inside the mash tun. I figure I don't need hose clamps since the tubing seems to hold onto the barbs pretty well. The false bottom does just rest on the bottom there's not really a way to secure it.


Thanks for the input guys!

if you don't stir your mash at dough in you WILL get a stuck sparge, it probably has nothing to do with the false bottom vs a braid (unless the FB is plastic and collapsing).
i can't fit a credit card between the rollers of my grain mill and my keggle mash tun with a false bottom has only gotten stuck when i didn't stir well at dough in or let it sit for 10 minutes before recirculating.

I always put the hot water in the cooler 1st, then stir in the grain. never a stuck mash drain.

when cracking the valve, make sure it's just a crack at the initial vorlauf. If you send out too much liquid too quickly you can create a vacuum unintentionally which will clog things up.

I always open the valve full out first thing then once the grain bed is set I turn it down. Never once had a stuck sparge with my false bottom also from morebeer.

farny said:

............I'm frustrated and put off that spending the extra money to improve my system has led to disaster. Any advice?

The false bottom is connected to the valve with some 3/8" silicone tubing. After the valve I have 3ft of 3/8" tubing into my boil kettle.

Thanks for any advice! Love the forums!

Click to expand...

While I was still adding equipment to my rig, invariably each time I added or changed something, it resulted in frustration and an extra hour to the brew day. I decided though that I just wasn't familiar with what it took to optimize the piece of equipment/new technique. Eventually after a few times I'd figure it out and I would be comfortable with the change and things were now even better.

First off make sure you give the mash a good stir after the the mash is finished. Let this settle a bit and then proceed with the vorlauf. After we mash in, the bits of the grain settle out over the time of the mash. If you were to slice a grain bed in half you would see the bigger pieces at the bottom and the smaller pieces at the top (including precipitated protein scum) This is the worst arrangement for a "filter" with the fine filter on top and the coarse at the bottom. By giving a good stir and starting your sparge before it has fully settled you can get a grain bed that is more uniform throughout which will then act as a better filter (less likely to stick). You likely will have to vorlauf a little longer, but that should be simple enough.

You might also try adding some extra water after mashing, stirring and then starting your sparge. I have found that when I do an adjunct brew (less malt) or use a lot of rye or wheat (gummy) that these are more prone to stick, but if I dilute the mash a little extra after the mash, but before starting the sparge I do not have any problems

tooldudetool said:

Hate to say it man, but go back to the braid! If it ain't broke don't fix it! But I do understand though, I've certainly lusted after brewery upgrades and been less than impressed. I'm a proud SS braid batch sparger, and I regularly get 90+% efficiency with a tight crush and some rice hulls, and IMHO it's way easier to add a $1 pound of malt to your brew to make up for efficiency than to spend all that time fly sparging and spending good cash on a false bottom. Contact morebeer and tell them their false bottom sucks and you want your money back, and go back to the braid

Click to expand...

I have to agree with this 100%. I just had the same problem as the OP on my last batch with a false bottom and had to transfer to another container, switch out the FB for SS braid, transfer back to the MLT and continue on with brew day.

Additionally, I have noticed that with a false bottom in a cooler, since you can't secure it to the bottom, very easily lets grain sneak under and through the outlet tube. So even when I vorlauf clear, by the time the MLT is drained I am getting some grain into my brew kettle. I'm 100% back on the SS braid and I just put my FB on Craigslist. By the time I'm ready to build the system I really want a new FB will be a trivial cost so I might as well let someone who wants it use it.

I noticed you used 3/8 vinyl tubing. It gets VERY flexible at mash temperature and is probably just collapsing under the weight of the grain. If you had good results with your SS braid and your only change was the false bottom, this would explain it. Try the thermoplastic tubing; it's much more rigid and is made for the heat. Your grain bill didn't look like it needed rice hulls, though they don't hurt. By the way, you can fly sparge with your SS braid if you want to try it...

I do always stir when I pour the grain in, what I meant was that I didn't stir every 15 min during the mash like I normally do. Stirring the mash right before vorlauf sounds like it could be a good idea to agitate the grain to keep it from embedding itself in the false bottom. I'll try that next time too. The tubing I use in the bottom is silicone which I was told is suitable for high temp.

The reason I went to a false bottom was that my efficiency started dropping and I pinned it to the fact that the SS braid was starting to kink. Might as well upgrade if I had to replace it anyways. Even after both of these stuck mashes my efficiency was higher than the last few brews the the braid. The beer came out pretty good too!

Thanks all!

I have the same false bottom & it works great for me. I removed the 3/8 elbow & never used it since I didn't want to use tubing in the mash tun. Instead, I use 1/2 inch cpvc pipe from the ball valve connected to a 1/2 inch 90 degree cpvc elbow thru the center hole of the false bottom. It holds down the false bottom nicely and the elbow hangs down thru the false bottom leaving very little wort left over. Hope you resolve the issue.

Are you adding the rice hills to the grain? I ask because I had problems which I traced to my practice of putting rice hills in the mash run, adding water, then adding grain. When added that way, rice hills tended to plug up the false bottom.

farny said:

The tubing I use in the bottom is silicone which I was told is suitable for high temp.

Thanks all!

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It is "suitable" for high temp, but when used in a false bottom/mash tun setup it tends to flatten out under the weight of the grain. You're using the clear type right? The opaque thermoplastic type is much stronger and should fix your problem. Or you could try PVC like another poster suggested. I really think your issue is mechanical based on the info you provided. Rice hulls are cheap insurance against a stuck mash from sticky additions, but won't help at all if the tube connecting your valve and false bottom is squished flat...

Does your false bottom lie flat on the base of the MLT? If not you will get grains underneath the false bottom, which could result in a stuck sparge. Possible reasons for the false bottom not lying flat on the base of the MLT are:

1. The false bottom is warped, and wont sit flat on a flat surface Ask for a replacement.
2. The base of the MLT is warped. Get a new MLT
3. The outlet elbow for the false bottom is so low that it prevents the rim of the false bottom from sealing on the base of the MLT. Raise the outlet. It is adjustable

When adding the strike water, drain a small amount out of the outlet, to flood the tubing with water. There is no way that your tubing will flatten when it is filled with water, as water is incompressible.


-a.

I have the same setup, except for in a 10 gallon cooler. I have brewed over 30 batches on this set up and never had a stuck mash. Maybe it is because I always use at least 1.5 quarts/lb. I add the grains to the water. I batch sparge with 170* water. I brew with lots of wheat and always keep some rice hulls handy. Hope this helps.

ron said:

I agree with the rice hulls, but I think 1 pound is too much. I usually just throw in a double handful, works for me.

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Depends what your mashing though, when i mashed with pumpkin i just threw the whole pound in.

Seriously when i can get a pound of rice hulls for 70c im not thinking of ways to save, just dump the whole stupid thing in and get the best drainage i can.

ajf said:

There is no way that your tubing will flatten when it is filled with water, as water is incompressible.

-a.

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Water is incompressible if in a sealed space, but the tubing is open to the underside of the false bottom and can simply flow out allowing the tubing to very easily flatten out. Try it, fill your mash tun with a gallon or two and see if you can squeeze the tube. I guarantee you can. And at mash temperatures it's VERY easy...

I use this tubing from morebeer. I live close to their warehouse so all my stuff is from them. When I add the rice hulls it's after I've already stirred in all my grain. I'll then pour in some rice hulls and mix again.

The false bottom does sit evenly on the bottom. And actually something I forgot to mention, on my second brew with the stuck mash I was able to open the valve all the way and shine my flashlight down the tubing. I could see all the way to the stainless elbow thus ruling out the tubing being pinched. It proves that the false bottom is sealing correctly against the walls of the mash tun. This leaves the only other option that the screen is simply being clogged.

I haven't brewed again yet but I probably will this coming weekend. Things I will keep in mind: use a whole pound of rice hulls, open valve very slowly, stir right before opening valve to agitate grain bed, use 1.5quarts per lb of grain. Possibly mash out?

Thanks again all!

An update:

I've brewed two batches since I last posted on here. I believed that the fitting that goes through the screen was getting pushed up agains the bottom of the mash tun which was sealing off any flow. So, my next batch I cut off a small piece of cpvc to act as a spacer and not let the screen get deformed downwards. It worked! However I'm still not fully convinced that this was the problem. I'll keep that spacer in there for the rest of my brews and hope that it works. But for now I'm a happy brewer!

I had the bottom of my cooler cut off the flow as well. I think I overheated my tun once and the bottom puckered in the center. Subsequent stirring resulted in grain getting under the false bottom and a really stuck mash. I like your solution. My solution was to switch to braid immediately. Problem solved but I batch sparge.

Good luck
Flask